Hi all, We noticed that you all added support for building s390 with clang, which is great! I have noticed a few warnings for which I will send patches but this one has me stumped. In file included from ../lib/crypto/sha256.c:16: In file included from ../include/linux/module.h:13: In file included from ../include/linux/stat.h:19: In file included from ../include/linux/time.h:6: In file included from ../include/linux/seqlock.h:36: In file included from ../include/linux/spinlock.h:51: In file included from ../include/linux/preempt.h:78: In file included from ../arch/s390/include/asm/preempt.h:6: In file included from ../include/linux/thread_info.h:38: In file included from ../arch/s390/include/asm/thread_info.h:26: ../arch/s390/include/asm/page.h:45:6: warning: converting the result of '<<' to a boolean always evaluates to false [-Wtautological-constant-compare] if (PAGE_DEFAULT_KEY) ^ ../arch/s390/include/asm/page.h:23:44: note: expanded from macro 'PAGE_DEFAULT_KEY' #define PAGE_DEFAULT_KEY (PAGE_DEFAULT_ACC << 4) ^ 1 warning generated. PAGE_DEFAULT_PAGE is always 0, meaning this function never does what it is supposed to. Is this intentional? It seems that commit 0b642ede4796 ("[PATCH] s390: default storage key") added this and it mentions that it can be overwritten at build time but I do not see any infrastructure for doing that. Any clarification that you can give so we can solve this warning would be much appreciated! Cheers, Nathan